Instance nodes of specific classes specification

TypeScript type: InstanceNodesOfSpecificClassesSpecification.

Returns nodes for instances of specific ECClasses.

Attributes

Name	Required?	Type	Default
Filtering
classes	Yes	MultiSchemaClassesSpecification | MultiSchemaClassesSpecification[]
excludedClasses	No	MultiSchemaClassesSpecification | MultiSchemaClassesSpecification[]	[]
instanceFilter	No	ECExpression	""
hideNodesInHierarchy	No	boolean	false
hideIfNoChildren	No	boolean	false
hideExpression	No	ECExpression	""
suppressSimilarAncestorsCheck	No	boolean	false
Ordering
priority	No	number	1000
doNotSort	No	boolean	false
Grouping
groupByClass	No	boolean	true
groupByLabel	No	boolean	true
Misc.
hasChildren	No	"Always" | "Never" | "Unknown"	"Unknown"
relatedInstances	No	RelatedInstanceSpecification[]	[]
nestedRules	No	ChildNodeRule[]	[]

Attribute: classes

Defines a set of multi schema classes that specify which ECClasses need to be selected to form the result.

Type	MultiSchemaClassesSpecification | MultiSchemaClassesSpecification[]
Is Required	Yes

// The ruleset has a specification that returns nodes for instances of `bis.PhysicalModel` class and all
// its subclasses.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: { schemaName: "BisCore", classNames: ["PhysicalModel"], arePolymorphic: true },
        },
      ],
    },
  ],
};

Attribute: excludedClasses

Defines a set of multi schema classes that prevents specified ECClasses and subclasses from being selected by classes attribute.

Type	MultiSchemaClassesSpecification | MultiSchemaClassesSpecification[]
Is Required	No
Default Value	[]

// The ruleset has a specification that returns nodes for all instances of `bis.Model` class
// excluding instances of `bis.DefinitionModel`, `bis.GroupInformationModel` and their subclasses.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: { schemaName: "BisCore", classNames: ["Model"], arePolymorphic: true },
          excludedClasses: { schemaName: "BisCore", classNames: ["DefinitionModel", "GroupInformationModel"], arePolymorphic: true },
        },
      ],
    },
  ],
};

Attribute: instanceFilter

Specifies an ECExpression for filtering instances of ECClasses specified through the classes attribute.

Type	ECExpression
Is Required	No
Default Value	""

// The ruleset has a specification that returns nodes for `bis.ViewDefinition` instances whose
// `CodeValue` property value ends with "View 1".
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: { schemaName: "BisCore", classNames: ["ViewDefinition"], arePolymorphic: true },
          instanceFilter: `this.CodeValue ~ "%View 1"`,
        },
      ],
    },
  ],
};

Attribute: hideNodesInHierarchy

When true, instances nodes produced by this specification are omitted and their children appear one hierarchy level higher. Note: only instance nodes are hidden - grouping nodes are not affected by this attribute.

Type	boolean
Is Required	No
Default Value	false

// The ruleset contains a root node specification for `bis.PhysicalModel` nodes which are grouped by class and hidden. This
// means class grouping nodes are displayed, but instance nodes are hidden and instead their children are displayed. The
// children are determined by another rule.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: { schemaName: "BisCore", classNames: ["PhysicalModel"], arePolymorphic: true },
          hideNodesInHierarchy: true,
        },
      ],
    },
    {
      ruleType: "ChildNodes",
      specifications: [
        {
          specType: "CustomNode",
          type: "child",
          label: "Child",
        },
      ],
    },
  ],
};

hideNodesInHierarchy: false	hideNodesInHierarchy: true

Attribute: hideIfNoChildren

Specifies whether nodes created through this specification should be hidden if they have no child nodes.

Type	boolean
Is Required	No
Default Value	false

// The ruleset contains root node specifications for two custom nodes which are only
// displayed if they have children. One of them has children and the other - not, so
// only one of them is displayed
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "CustomNode",
          type: "2d",
          label: "2d Elements",
          hideIfNoChildren: true,
        },
        {
          specType: "CustomNode",
          type: "3d",
          label: "3d Elements",
          hideIfNoChildren: true,
        },
      ],
    },
    {
      ruleType: "ChildNodes",
      condition: `ParentNode.Type = "2d"`,
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: { schemaName: "BisCore", classNames: ["GeometricElement2d"], arePolymorphic: true },
        },
      ],
    },
    {
      ruleType: "ChildNodes",
      condition: `ParentNode.Type = "3d"`,
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: { schemaName: "BisCore", classNames: ["GeometricElement3d"], arePolymorphic: true },
        },
      ],
    },
  ],
};

hideIfNoChildren: false	hideIfNoChildren: true

Attribute: hideExpression

When specified ECExpression evaluates to true, nodes produced by this specification are omitted and their children appear one hierarchy level higher.

Type	ECExpression
Is Required	No
Default Value	""

// The ruleset contains root node specifications for two custom nodes which are only
// displayed if they have children. One of them has children and the other - not, so
// only one of them is displayed
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "CustomNode",
          type: "2d",
          label: "2d Elements",
          hideExpression: `ThisNode.HasChildren = FALSE`,
        },
        {
          specType: "CustomNode",
          type: "3d",
          label: "3d Elements",
          hideExpression: `ThisNode.HasChildren = FALSE`,
        },
      ],
    },
    {
      ruleType: "ChildNodes",
      condition: `ParentNode.Type = "2d"`,
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: { schemaName: "BisCore", classNames: ["GeometricElement2d"], arePolymorphic: true },
        },
      ],
    },
    {
      ruleType: "ChildNodes",
      condition: `ParentNode.Type = "3d"`,
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: { schemaName: "BisCore", classNames: ["GeometricElement3d"], arePolymorphic: true },
        },
      ],
    },
  ],
};

hideExpression evaluates to false	hideExpression evaluates to true

Attribute: suppressSimilarAncestorsCheck

Specifies whether similar ancestor nodes' checking should be suppressed when creating nodes based on this specification. See more in Infinite Hierarchies Prevention page.

Type	boolean
Is Required	No
Default Value	false

// The ruleset contains a root node specification that returns the root `bis.Subject` node. Also, there are two
// child node rules:
// - For any `bis.Model` node, return its contained `bis.Element` nodes.
// - For any `bis.Element` node, return its children `bis.Model` nodes.
// Children of the root `bis.Subject` are all in the single `bis.RepositoryModel` and some of their children are in the same
// `bis.RepositoryModel` as their parent. This means the `bis.RepositoryModel` node has to be repeated in the hierarchy, but
// that wouldn't happen due to duplicate nodes prevention, unless the `suppressSimilarAncestorsCheck` flag is set.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: { schemaName: "BisCore", classNames: ["Subject"] },
          instanceFilter: `this.ECInstanceId = 1`,
          groupByClass: false,
          groupByLabel: false,
        },
      ],
    },
    {
      ruleType: "ChildNodes",
      condition: `ParentNode.IsOfClass("Model", "BisCore")`,
      specifications: [
        {
          specType: "RelatedInstanceNodes",
          relationshipPaths: [
            {
              relationship: { schemaName: "BisCore", className: "ModelContainsElements" },
              direction: "Forward",
            },
          ],
          groupByClass: false,
          groupByLabel: false,
        },
      ],
    },
    {
      ruleType: "ChildNodes",
      condition: `ParentNode.IsOfClass("Element", "BisCore")`,
      specifications: [
        {
          specType: "RelatedInstanceNodes",
          relationshipPaths: [
            [
              {
                relationship: { schemaName: "BisCore", className: "ElementOwnsChildElements" },
                direction: "Forward",
              },
              {
                relationship: { schemaName: "BisCore", className: "ModelContainsElements" },
                direction: "Backward",
              },
            ],
          ],
          suppressSimilarAncestorsCheck: true,
          groupByClass: false,
          groupByLabel: false,
        },
      ],
    },
  ],
};

Attribute: priority

Controls the order in which specifications are handled — specification with higher priority value is handled first. If priorities are equal, the specifications are handled in the order they appear in the ruleset.

Type	number
Is Required	No
Default Value	1000

// This ruleset produces a list of `bis.PhysicalModel` and `bis.SpatialCategory` instances and groups them by
// class. "Spatial Category" group will appear first because it has been given a higher priority value.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          priority: 1,
          classes: { schemaName: "BisCore", classNames: ["PhysicalModel"], arePolymorphic: true },
        },
        {
          specType: "InstanceNodesOfSpecificClasses",
          priority: 2,
          classes: { schemaName: "BisCore", classNames: ["SpatialCategory"], arePolymorphic: true },
        },
      ],
    },
  ],
};

Attribute: doNotSort

By default, nodes are sorted by their display label. This attribute allows suppressing sorting of nodes returned by this specification, which can substantially improve performance when large numbers of nodes are involved. With this attribute set to true, the order of returned nodes is undefined.

Type	boolean
Is Required	No
Default Value	false

// The ruleset has a specification that returns unsorted `bis.Model` nodes - the order is undefined.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: [{ schemaName: "BisCore", classNames: ["Model"], arePolymorphic: true }],
          doNotSort: true,
        },
      ],
    },
  ],
};

Attribute: groupByClass

Controls whether returned instances should be grouped by ECClass.

Type	boolean
Is Required	No
Default Value	true

// The ruleset contains a specification that returns `bis.Model` nodes without grouping them
// by class.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: [{ schemaName: "BisCore", classNames: ["Model"], arePolymorphic: true }],
          groupByClass: false,
        },
      ],
    },
  ],
};

groupByClass: false	groupByClass: true

Attribute: groupByLabel

Controls whether returned instances should be grouped by label.

Label grouping node is created only if all of these conditions match:

• There are at least two nodes with the same label.
• There's at least one sibling node with a different label.

Type	boolean
Is Required	No
Default Value	true

// The ruleset contains a specification that returns `meta.ECPropertyDef` nodes without grouping them
// by label.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: [{ schemaName: "ECDbMeta", classNames: ["ECPropertyDef"] }],
          groupByLabel: false,
        },
      ],
    },
  ],
};

groupByLabel: false	groupByLabel: true

Attribute: hasChildren

Generally, when a node is created, the rules engine has to determine whether it has children before returning it. This requires evaluating child node rules and, usually, executing additional queries. This attribute allows telling the engine that nodes created by this specification always or never have children, which may substantially improve performance of creating nodes in cases when getting child nodes is expensive.

In case when the attribute value "lies":

• When set to Always, the returned nodes always have hasChildren flag set to true. Requesting children for such nodes returns empty list. It's up to the UI component to handle the case of parent node saying it has children but data source not returning any.

• When set to Never, the returned nodes always have hasChildren set to false. Requesting children for such nodes returns empty list even if there are child node rules that define children for it.

Type	"Always" | "Never" | "Unknown"
Is Required	No
Default Value	"Unknown"

// This ruleset produces a hierarchy of a single root node that hosts a list of `Model` instances. Assuming all
// iModels contain at least one model, the result of this ruleset can be computed quicker by setting
// `hasChildren` attribute to `"Always"`.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "CustomNode",
          type: "T_ROOT_NODE",
          label: "My Root Node",
          hasChildren: "Always",
        },
      ],
    },
    {
      ruleType: "ChildNodes",
      condition: `ParentNode.Type="T_ROOT_NODE"`,
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: [{ schemaName: "BisCore", classNames: ["Model"], arePolymorphic: true }],
        },
      ],
    },
  ],
};

hasChildren: "Always"	hasChildren: "Never"

Attribute: relatedInstances

Specifications of related instances that can be used when creating the nodes. There are several use cases when this is useful:

• When there's a need to only load instances that have a related instance. Providing a related instance specification with isRequired set to true filters-out the instances that don't have the related instance.

• When there's a need to filter instances by a related instance value. The alias attribute may then be used in the instanceFilter attribute to reference related instance property values.

• When there's a need to group by related instance property values. Related instance classes are included when looking for grouping rules, which allows using related instance values for property grouping.

• When there's a need to customize nodes based on related instance property values. Related instance classes are included when looking for customization rules, which allows referencing related instances and their properties in customization rule ECExpressions by their alias.

Type	RelatedInstanceSpecification[]
Is Required	No
Default Value	[]

// The ruleset contains a root nodes' specification that returns nodes for `bis.Elements` that are in
// a category containing "a" in either `UserLabel` or `CodeValue` property.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: [{ schemaName: "BisCore", classNames: ["GeometricElement3d"], arePolymorphic: true }],
          relatedInstances: [
            {
              relationshipPath: [
                {
                  relationship: { schemaName: "BisCore", className: "GeometricElement3dIsInCategory" },
                  direction: "Forward",
                },
              ],
              alias: "category",
              isRequired: true,
            },
          ],
          instanceFilter: `category.UserLabel ~ "%a%" OR category.CodeValue ~ "%a%"`,
        },
      ],
    },
  ],
};

Attribute: nestedRules

Specifications of nested child node rules that allow creating child nodes without the need of supplying a condition to match the parent node.

This is useful when the same instance node at different hierarchy levels needs to have different child nodes. Specifying a child node rule at the root level with condition to match the instance ECClass makes the rule create children for all nodes of that ECClass. When that's not desired, different child node rules may be specified as nested rules for specifications that return instance nodes of the same ECClass - that makes them have different children.

Type	ChildNodeRule[]
Is Required	No
Default Value	[]

// The ruleset contains two root nodes' specifications:
// - The first one returns `bis.SpatialCategory` nodes
// - The second one returns `bis.PhysicalModel` nodes and also has a nested child node rule
//   that creates a static "child" node.
// Nested rules apply only to nodes created by the same specification, so the static "child"
// node is created only for the `bis.PhysicalModel`, but not `bis.SpatialCategory`.
const ruleset: Ruleset = {
  id: "example",
  rules: [
    {
      ruleType: "RootNodes",
      specifications: [
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: [{ schemaName: "BisCore", classNames: ["SpatialCategory"] }],
          groupByClass: false,
        },
        {
          specType: "InstanceNodesOfSpecificClasses",
          classes: [{ schemaName: "BisCore", classNames: ["PhysicalModel"] }],
          groupByClass: false,
          nestedRules: [
            {
              ruleType: "ChildNodes",
              specifications: [
                {
                  specType: "CustomNode",
                  type: "T_CHILD",
                  label: "child",
                },
              ],
            },
          ],
        },
      ],
    },
  ],
};

Deprecated attributes

Attribute: arePolymorphic

Tells whether selecting instances from ECClasses specified in classes and excludedClasses attributes should be polymorphic or not.

The attribute was replaced by arePolymorphic attribute specified individually for each class definition under classes and excludedClasses attributes. At the moment, to keep backwards compatibility, this attribute acts as a fallback value in case the flag is not specified individually for a class definition.

Type	boolean
Is Required	No
Default Value	false